Jan 10 (Reuters) - An international gold shipment worth about $13 million was stolen from security firm Brink’s Co , a source with knowledge of the matter told Reuters on Wednesday.

The theft occurred on Dec. 6 and would result in a fourth-quarter pretax charge of about $11 million, Brink’s said in a statement.

The robbery is under investigation and the customer affected by the theft has been reimbursed, the company said, without giving any more details.

“When Brinks has a loss they cut a check to their customer instantaneously, and I mean like the next day. Brinks doesn’t wait for insurance to come back to them to reimburse their customers the way some competitors do,” another source said.

The company has been the victim of previous robberies, including one in 2013, where robbers dressed as police and armed with machineguns stole 120 parcels of diamonds worth $50 million from a van belonging to Brink's, at the runway of Brussels Airport. (reut.rs/2CZnBgH)

Despite the charge, Brink’s, which specializes in secure transportation and handling of currency and valuables, said it continues to expect to post strong fourth-quarter results.